Slip mounting for well tools



March 31, 1959 J. A. WILSON ETAL 2,879,851

' SLIP MOUNTAINS FOR WELL TOOLS Filed Aug. 1, 1955 2 Sheets Sheet 1 z Z6 Z5 /Z James A. Wilson 5002! B. A/fer F g. 1 ATTORNEYS INVENTORS March 3l,"1959 i J. A. Wl LSON ETAL 2,879,851

SLIP MOUNTING FOR WELL TOOLS Filed Aug. 1, 1955 2 Sheets-Sheet 2 INVENTORS James A. Wilson 500' B. A/far Fig. 9 BY ATTORNEYS United States Patent SLIP MOUNTING FOR WELL TOOLS James A. Wilson and Scott B. Alter, Dallas, Tex., as-

signors to Equipment Engineers, Inc., Dallas, Tex., a corporation of Texas Application August 1, 1955, Serial No. 525,525

3 Claims. (Cl. 166-216) This invention relates to new and useful improvements in well tools and more particularly to means for mounting the slips thereof.

One object of the invention is to provide improved means for mounting the gripping members of a well tool to permit the disengagement of the members and the removal of the tool when said members cannot be released in the usual manner.

A particular object of the invention is to provide an improved mounting for a slip of a tubing anchor or other well tool which includes frangible means for releasably connecting the slip to an expander whereby said slip may be disconnected from the expander in the event that it is impossible to retract and maintain retraction of said slip from gripping position.

An important object of the invention is to provide an improved slip mounting, of the character described, wherein the slips are supported on a well tool in the usual manner and shear elements releasably connect said slips to an expander to prevent loss of said slips and disconnection thereof from the well tool when the same become non-retractable.

A further object of the invention is to provide an improved slip mounting, of the character described, wherein the shear elements may be made integral with the slip or slips or separately thereof for slidably connecting said slip or slips or which may be carried by members to which said slip or slips are slidably connected.

A construction designed to carry out the. invention will be hereinafter described, together with other. features of the invention.

The invention will be more readilyunderstood from a reading of the following specification and by reference to the accompanying drawings, whereinexamples of the invention are shown, and wherein:

Fig. l is a longitudinal, sectional view of a well tubing anchor having its slips mountedin accordance with the invention and retracted,

Fig. 2 is a view, similar to Fig. 1, of theanchor with its slips set in gripping engagement with the casing,

Fig. 3 is a horizontal, cross-sectional view, taken on the line 33 of Fig. 1, r

Fig. 4 is a perspective view of one of the slips and its shear elements,

Fig. 5 is an enlarged, horizontal, cross-sectional view, taken on the line 55 of Fig. 2,

Fig. 6 is an enlarged, transverse, vertical, sectional view of one of the slip openings of the expander and its groove for receiving one of the. shear elements,

Fig. 7 is a perspective view of a modified slip,

Fig. 8 is a horizontal, cross-sectional view showing another modification of the slip and its mounting,

Fig. 9 is a front elevational view'of the modified slip of Fig. 8,

2,879,851 Patented Mar. 31, 1959 Fig. 10 is a side elevational view of the modified slip in retracted position, and

Fig. 11 is a side elevational view of the slip in expanded or set position.

In the drawings, the numeral 10 designates a tubing anchor or other well tool connected in a string of tubing 11 for axial movement and positioning within a well casing 12. The tubing anchor includes an axial, tubular support or mandrel 13 connected by upper and lower screw-threaded coupling collars. 14 and 15 to the tubing 11. An expander member or head 16 is screw-threaded upon the upper end of the lower coupling collar 15 and extends thereabove in concentric relation to the mandrel 13 for coaction with a plurality of gripping members or slips 17, as will be explained. The slips are supported by the usual links 18 which are pivotally attached to the upper ends of said slips by transverse pins 19 and which have crossheads 20 at their upper ends. A connector collar or slip supporting member 21 is slidable on the mandrel above the expander head 16 and has longitudinal, radial T-slots 22 for receiving the upper ends of the links 18 and their crossheads 20.

The connector collar 21 is rotatably suspended from a drag and lock device 23 having an annular adapter or collar 24 at its lower end slidable on the mandrel 13. For rotatably connecting the collars 21 and 24, a segmental swivel ring 25 surrounds the adjacent ends of said collars which are reduced in diameter and have external, radial grooves 26 for receiving the ring. The latter is U-shaped in cross-section to provide internal, radial flanges for engagement with the grooves 26. A retaining sleeve 27 is fastened to the collar 24 in overlying relation to said collar and the collar 21 for confining the segmental ring 25 and link cross heads 20 against displacement. Due to this connection, it is manifest that the drag and lock device 23 may undergo rotation relative to the collar 21 and the slips 17 suspended therefrom.

The device includes a cylindrical shoe housing 29 screwthreaded in the upper end of the collar 24 and extending upwardly therefrom in concentric relation to the mandrel. A cylindrical case or sleeve 30 surrounds the lower portion of the upper collar and has its lower end screwthreaded on the upper end of the shoe housing 29 in spaced relation to the collar 24. As shown by the numeral 31, the ends of the housing are reduced externally to provide shoulders for engagement with the case and collar. A plurality of friction pads or shoes 32 are disposed within longitudinal, radial grooves or recesses 33 formed in the outer surface of the housing and have inwardly-ofiset ends 34 for confining engagement by the overhanging upper end of the sleeve 27 and an annular flange 35 depending axially from the case 30 whereby the shoes project from the recesses. The shoes are of internally recessed construction and include flat, longitudinal springs 36 for engagement with bosses 37 formed on the housing 29 whereby said shoes are urged outwardly into engagement with the casing 12. Manifestly, the frictional engagement of the shoes 33 with the casing resists movement of the drag and lock device 23.

For releasably connecting the case 30 to the upper collar 14, a pin 38 and lariat slot 39 are provided (Figs. 1-3). Although the position of the pin and slot may be reversed, said pin is shown as projecting externally from the collar and the circumferentialportion or groove 40 of said slot is formed in the internal surface of the case. Of course, the longitudinal portion or leg of the slot extends upwardly to the upper end of the case and may extend entirely therethrough to the exterior of said case.

When the pin 38 is engaged in the circumferential groove 40 of the slot 39, the device 23 is in its raised or upper position and the upper end of the shoe housing 29 abuts the lower end of the upper coupling collar 14. As shown in Fig. 1, the slips 17 and their links 18 are raised with respect to the expander head 16 so as to be maintained in retracted position by the engagement of the pin with the groove. When it is desired to expand or set the slips, the tool or anchor 10 is rotated by turning the tubing 11 to move the pin 39 into registration with the longitudinal leg of the slot 39. This relative rotation is permitted by the frictional engagement of the shoes 33 with the casing 12 which holds the device 23 and its case 30 stationary. As will be explained, the slips are set upon relative upward movement of the expander head 16 with the mandrel l3 and tubing.

Each slip 17 has the usual serrated or toothed outer surface 41 and a pair of apertured ears or lugs 42 on its upper end (Fig. 4) for receiving the pivot pin 19. A plurality of longitudinal, radial openings or slots 43 are formed in the expander head to receive the slips (Figs. and 6). In order to expand the slips into gripping position upon relative upward movement of the expander head, each slip is provided with a pair of opposed, outwardly and downwardly inclined or diagonal guide fins or ribs 44 on its sides for engagement with complementary channels or grooves 45 in the side walls of the slots 43. Preferably, the coacting fins and grooves terminate short of the lower ends of the slips and slots. It is noted that the slips remain stationary with the device 23 upon relative upward movement of the head with the mandrel 13 and tubing 11 and that the swivel ring 26 permits rotation of said slips with said head, mandrel and tubing relative to said device.

Frequently, a tubing anchor or other well tool remains in a well for an appreciable time without being removed or repositioned, whereby the tool becomes corroded or stuck and difficult to remove. In attempting to retract slips under these conditions, it is not unusual to fracture the links 18 or otherwise entirely disconnect the slips from the tool whereby said slips are lost in the well or bind said tool against removal. In order to permit disconnection of the slips 17 from the expander head 16 and inward movement of said slips to retracted or noncxpanded position, the fins or ribs 44 are frangible and are in the form of shear elements or strips. Either the material of the fins may be frangible or said fins may be of such thinness as to fracture upon the exertion of a predetermined force. In any event, the fins are adapted to fracture and permit inward movement of the slips when it is impossible to retract and maintain retraction of said slips by relative downward movement of the expander head.

A modified slip 47 is shown in Fig. 7 and has an inclined channel or groove 48 in each side for engagement by a separate shear element, fin or rib 49 of frangible material. Slips of this construction function in the same manner as the slips 17 and are mountable in the slots 43 of the expander head; however, the modified slips are reuseable after fracturing of the fins 49 since it is only necessary to replace the latter.

Another modification of the slip is shown in Figs. 8-11 and includes a base member or pad 50 having a shear element in the form of an upright fin or rib 51 of frangible material on each side at its inner longitudinal margin. A modified opening or slot 52 is formed in a head 53, similar to the head 16, and has upright channels or grooves 54 in its side walls for engagement by the fins 51 (Fig. 8). It is noted that the particular shape of the fins is immaterial and that any suitable shear element may be employed to releasably connect the base member of the slip to the head. As shown by the numeral 55, the outer surface of the pad 50 is inclined outwardly and downwardly and has a dovetail tongue and groove connection 56 with a slip member 57 whereby'the slip mem- 4 bet is slidably connected to said pad. Apertured ears or lugs 58, similar to the lugs 42, are formed on the upper end of the slip member 57 for connection to the link 18 by the pivot pin 19 whereby said member is expanded and retracted by longitudinal movement relative to the pad. Although the pad 50 remains stationary within the slot 52, its fins or shear elements 51 are adapted to fracture when it is impossible to retract the slip member by sliding movement. As a result, only the pad must be replaced and the slip member is reuseable. Of course, the fins 51 may be formed separately of the pad in the same manner as the fins 49. It is noted that the slot 52 is of sufficient depth to contain the pad and expanded slip member after fracturing of the fins. Although the invention is shown and described in connection with a tubing anchor, it is manifest that the frangible mounting of the slips is applicable to other well tools. Further, inasmuch as one slidable slip mounting would function in certain designs of well tools, it should not be construed that more than one such mounting is essential.

The foregoing description of the invention is explanatory thereof and various changes in the size, shape and materials, as well as in the details of the illustrated construction may be made, within the scope of the appended claims without departing from the spirit of the invention.

What we claim and desire to secure by Letters Patent is:

1. A well tool comprising a body, a slip member, an expander member for said slip member mounted on said body, means for mounting said slip member for relative sliding movement on said body, relative sliding movement between said members in one direction causing expansion of said slip member outwardly of said body and in the opposite direction causing retraction of said slip member inwardly of said body, frangible means mounted on one of said members, the other of said members having an inclined camming surface, said frangible means being in slidable camming engagement with said camming surface for expanding and retracting said slip member, said frangible means being adapted to be fractured when said slip member does not retract under normal slip member retracting operating conditions to permit retraction of said slip member and removal of said tool from the well without fracturing said mounting means.

2. A well tool comprising a body, a slip member, an expander member for said slip member mounted on said body, means for mounting said slip member for relative sliding movement on said body, relative sliding movement between said members in one direction causing expansion of said slip member outwardly of said body and in the opposite direction causing retraction of said slip member inwardly of said body, and frangible means comprising a longitudinally-extending fin positioned on each side of one of said members, complementary grooves in the other of said members inclined to the axis of said body in which said fins travel, said frangible means being adapted to be fractured when said slip member does not retract under normal slip member retracting operating conditions to permit retraction of said slip member and removal of said tool from the well without fracturing said mounting means.

3. A well tool comprising a body, a slip member having a surface inclined to the axis of said body, a slot formed by spaced side walls positioned in said body, grooves formed in said side walls, an expander pad having a surface inclined to the axis of said body opposite to the inclination of the surface of said slip member and having a frangible fin extending outwardly on each side thereof, said pad being mounted in said slot with said fins positioned in said grooves to hold said pad outwardly from the inner end portion of said slot, means for mounting said slip member for relative sliding movement on said body, relative sliding movement between said members in one direction causing expansion of said slip member outwardly of said body and in the opposite direction causing retraction of said slip member inwardly of said body,

5 6 said frangible fins being adapted to be fractured when Referen'es Cited in the file of this patent said slip member does not l'CtIfiCt under noqnal slip mem- UNITED STATES PATENTS ber retractmg operatmg condmons to permlt retractlon of both said pad and said slip member and removal of said 2:85 3:3

t 1 tool from the well wlthou fracturmg sald mountmg 5 2,323,085 Davis June 29, 1943 means 2,355,199 Bassinger Aug. 8, 1944 

